Giant’s Prototype TT machine
By Matt Pacocha
Giant Bicycles had something special at the Amgen Tour of California: Two teams riding a time trial bike it’s developing.
This isn’t out of the ordinary, except for the fact that one of the teams has a different bike sponsor. You’ll notice that Rabobank and Columbia are on quite similarly designed bikes, but one says “Giant” on its downtube, while the other sports a “Highroad techdev” label.
This story has roots that go back to well before last year’s Tour de France when the Highroad, then sponsored by Giant, required that the manufacturer contract an aerodynamic specialist to help build a time trial bike for the team and faster than anything its competition had.
Tom Davies, Giant’s team liaison put Simon Smart, a British F1 aerodynamicist, in touch with the brand. Smart’s collaboration with Giant engineers resulted in the Giant time trial prototype that both Rabobank and Highroad are currently using. Giant produced the bikes for its teams. The latest version, the fourth, is the one currently in use by the Rabobank team.
The bike itself is like hardly any other. And Rabobank’s prototype is different from the version we saw at last year’s Tour de France.
“It’s a work in progress,” said former VeloNews tech editor Andrew Juskaitis, who is now Giant’s communications manager. “It doesn’t have a name; it’s simply called a TT bike right now. This is generation four.”
The Rabobank prototype differs from Highroad’s techdev prototype in seemingly small ways that make a big difference. The cable routing is slightly cleaner. The brake placement has been refined and Giant developed a new version of its proprietary front brake. The seat post, too, is different, said Juskaitis, pointing to the seat post, which operates on a shim system, much like the reverse of its TCR integrated mast design.
“It’s kind of like an integrated seatmast, meaning it’s ultra thin, [short] and it uses spacers to move it up or down,” said Juskaitis. “It allows us to make an ultra short, ultra light seatpost.”
Another major change between the two versions of this bike on the circuit it that the older model features forms that fall slightly outside of the UCI’s 3:1 ratio rule.
“The versions that you saw earlier on like at the Tour de France had a little bit wider profile,” said Juskaitis. “We were made aware of that rule very early on and so this generation four prototype adheres to that 3:1 ratio. So, if the UCI chose to enforce the rule right now we would have no problem meeting it.”
Just because the bike meets the UCI’s rule doesn’t mean it’s slow.
“We claim this is the fastest bike in the world,” he said. “Even when comparing this to UCI illegal bikes, it’s faster.”
It’s the little things that Giant changes make its bike the fastest. An example is an opening on the underside of the fork crown. According to Giant a wheel generates airflow and the opening on the underside of the fork crown allows that air to move through the structure. The result, said Juskaitis, creates a lower aerodynamic drag than if it were closed off. Giant also tries to make all of the frame’s leading edges as vertical as possible, because testing has shown that to be the fastest.
The bike is currently available to the team in three sizes, but the bikes are made in different molds than those used for a production bike. The team molds require a specialist to lay the carbon fiber into the mold and set the bladders. It takes two days to produce a prototype, whereas two or three production frames can be produced from a production mold every day. The bikes intricate front end also requires special attention to achieve its shape.
“This front end is super, super complex,” said Juskaitis. “In order to form it in a mold required us to introduce a new technology; a new type of bladder molding that actually takes the shape of [the form it’s molding.] So, this requires a shaped bladder. It’s super complex and it takes a long time to get it right.”
Stiffness is another attribute that has been changed after the team’s comment.
“We’ve been working on different lay-ups,” said Juskatis. “We’re trying to make it a little bit stiffer through the bottom bracket area. That’s the one thing the team keeps asking us for — a stiffer bottom bracket.”
Giant’s road product manager, Pierre Medas, added more detail.
“Because you are using an aero down tube they’re going to be very, very soft at the front end,” said Medas. “And they keep asking for the maximum stiffness at the front end of the bike. The lay up schedule was very tricky, very difficult to develop for the downtube.
Giant’s reps say that the fifth generation’s changes have already been decided on and should be ready for the start of the Grand Tour season.
Expecting to buy one in 2010 isn’t probably so realistic.
“We’re still weighing the cost benefit analysis,” said Juskaitis. “We need to determine how many we’re going to sell. And if we’re only going to sell a couple hundred then it just doesn’t make sense.”